Jam detection apparatus for a sheet feeder



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Jan. 1, 1963 H; R. DI VETO 3,07 ,373

JAM DETECTION APPARATUS FOR A SHEET FEEDER Filed NOV. 4, 1960 v 2 Sheets-Sheet 1 INVENTOR. H/LL/ARD RD/ l zro. I

ATTORNEY- Jan. 1, 1963 H- R. D] VETO JAM DETECTION APPARATUS FOR A SHEET FEEDER 2 Sheets-Sheet 2 Filed NOV. 4, 1960 Fig. 2.

76 INVENTOR. hZAA/ARD R. D/ VETO.

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United States Patent 3,071,373 Patented Jan. 1, 1963 Free 3,071,373 JAM DETECTION APPARATUS FOR A SHEET FEEDER Hilliard R. Di Veto, Plymouth, Mich, amignor to Burroughs Corporation, Detroit, Mich, a corporation of Michigan Filed Nov. 4, 1966, Ser. No. 67,304 Claims. (Cl. 271-57) This invention relates generally to sheet handling apparatus and more particularly to a jam detection apparatus therefor.

It is an object of this invention to provide a jam detection apparatus for a sheet feeder in which a rotating detector member mounted on and in cooperation with a drive roller stops rotation and is displaced from a normal position responsive to the stoppage of a sheet in transport.

It is an additional object to provide a jam detection apparatus for a sheet feeder in which a rotating detector member mounted coaxially with a drive roller is displaced from a normal position response-to a change in relative angular velocities of the drive roller and rotating indicator member.

It is a further object to provide a jam detection apparatus for a sheet feeder in which constantly rotated drive roller operates to displace in an axial direction a coaxially mounted detector roller subsequent to decrease in angular rotation of the detector.

It is a further object to provide a jam detection apparatus for a sheet feeder in which a drive roller having a relatively low coefficient of friction cooperates with a coaxially mounted detector roller having a relatively high coefiicient of friction and operates to displace the detector roll in a rectilinear direction subsequent to its termination of rotation responsive to engagement with a stopped sheet.

It is a still further object of this invention to provide a jam detection apparatus for a sheet in transport including a drive roller which operates to transmit a rectilinear movement to a detector member responsive to its stoppage of a sheet whereby the operating means for the drive roller will be inhibited.

These and other objects of this invention will become more apparent upon consideration of the rolling description, taken together with the accompanying drawings, in which:

FIGURE 1 is a plan view of a portion of a sheet trans port system with parts broken away;

FIG. 2 is an elevation showing a pair of opposed rollers with the drive roller having the present invention incorporated therewith;

FIG. 3 is a cross sectional view showing the detail of the detector roller and related parts.

FIG. 4 is a view similar to FIG. 3 and showing the parts in a jam detecting position.

In general, this invention provides a detector member coupled to a continuously rotated drive roller. The detector member is mounted coaxially on the drive roller and rotates freely therewith so long as the sheet is moving freely past the detector member. When a sheet stops indicating a jam condition or its speed has a marked decrease indicating an impending jam condition, the drive roller will impart through an intermediate member an axial movement to the detector member to close a switch and shut off the transport motor.

FIG. 1 shows a portion of the sheet transport system including side frame 26 which provides a stationary support at the left side of the sheet path. Side frame 20 has rigidly mounted thereon a U shaped channel 22 adapted to receive and contain the left marginal portion of a sheet 24. Extending laterally from side frame 20 are a plurality or" shafts 26 of which two are shown. A plurality of upper and lower guide rails 28 are slidably mounted on shafts 26 and are transversely movable to provide a guideway to accommodate sheets of varying widths. Also shown in FIG. 1 are a plurality of upper idler rollers 39 which engage the upper surface of the sheets in transport. Each idler roll is mounted in a freely rotatable manner on side frame 20.

A drive roller 32 is mounted in opposition to each idler roller 30. The sheet 24 is thus supported at one edge between the opposed rolls and supported centrally and at the other edge between upper and lower horizontal guide rails 28. I am detection means herein embodied as detector roller 34 is mounted coaxially with roll 32 in a manner more to be shown more clearly in FIG. 2. Disposed about the periphery of detector roll 34 are a plurality of 'circumferentially extending portions or rings 36 in a parallel spaced relationship. Rings 36 extend beyond the periphery of roll 34 and are formed of a resilient material or material having a greater coeflicient of friction than that of the peripheral portion of roll 32.

The parts in FIG. 2 are shown in a normal position when the sheet 24 is moving at its normal rate of travel between the rollers. The left hand edge portion of detector roller 34 is slightly displaced from the right hand end portion of drive roller 32. Auxillary side frame 20 is mounted on base 46 and has mounted thereon a motor control switch 42. The switch is of the normally open type and has a switch contact 44 and a movable switch actuating arm 46. Detector roller 34 carries at its right end a switch actuating button 54) which is adapted to move actuating arm 46 rightwardly to close switch 42. The operating means for the sheet transport system, drive motor 52, is connected to a suitable power source and is utilized to transmit a drive through drive shaft 54. It will be appreciated that a plurality of drive rollers 32 are utilized in the transport system along the sheet path of travel and each is coupled to the drive motor 52 by intermediate drive means and rotated at a constant rate. For simplicity and straightforwardness of exposition, transmission of drive is shown by means of a belt 56 between drive shaft 54 and shaft 58 on which drive roll 32 is mounted. Motor control switch 42 is connected in the power supply circuit of drive motor 52 in a 'welll known manner so that its closure is operable to interrupt the power supply to the drive motor and stop the transmission of drive to the sheet transport system.

FIG. 3 shows drive roller 32' mounted on shaft 58 and having two concentric, circular, cut-out portions 62 and 64. A threaded member 66 is provided with a threaded head portion 68 and a shaft portion 76. The threaded member has its shaft portion 76 retained in a fixed position in cut-out portion 62 by a set screw 72 seated in drive roller 32. Contained in cut-out portion 64 is a helical return spring 74 retained between an extended end portion 75 of detector roller 34 and the threaded head portion 68 of member 66. End portion 75 is cylindrical in shape and freely movable axially within cut-out portion 64. The structure of detector roller 34 is shown to include in addition to the circumferentially extending rings 36 an internal threaded portion 76 which is adapted to mate with threaded head portion 68.

FIG. 4 shows the detector roller in a jam indicating position in which it has been displaced axially from drive roller 32. Spring 74 is in a state of compression and the internal threaded portion 76 has moved outwardly on threaded head portion 68 of member 66.

Made of Operation During normal operation of the sheet transport system, sheets are moved at a relatively constant speed in the system in the manner indicated in FIG. 1. When sheets pass between opposed drive roller 32 and idler roller 30, they may become stopped due to misalignment, a multiple document condition, a malfunctioning drive assembly or for a number of other reasons. When this occurs it becomes imperative to stop the sheet transport system immediately so that a pile up condition and resultant sheet multilation can be minimized. During normal sheet transport, each sheet is engaged on its upper surface by the periphery of idler roller 30 and on its lower surface by the periphery of drive roller 32 and rings 36 of detector roller 34. The employment of the resilient rings gives the engaging surface of detector roller 34 a higher coefiicient of friction than that of the constantly revolved drive roller. So long as the sheet moves at a normal speed, the drive roller and the detector roller will be rotated at substantially the same angular velocity. During normal operation, the detector roller 34 is spaced longitudinally with a small mechanical clearance from the drive roller 32 as shown in FIGS. 2 and 3. The switch actuating button 50 carried at the end of detector roller 34 :is accordingly displaced from the actuating arm 46 of motor control switch 42.

An impending jam condition is sensed by the detector roller 34 as soon as a sheet 24 begins to slow down. Detector roller 34 will respond to the change in speed and its rate of angular rotation will decrease relative to the constant rate at which drive roller 32 is being driven. Drive roller 32 will begin to slip on the sheet. With reference to FIG. 3, it will be seen that threaded member 66 has its shaft 70 fixed to drive roller 32. As the rotation of detector roller 34 decreases relative to that of the drive roller 32, the detector roller will be displaced axially to the right by the action of the threaded head portion 68 advancing the detector roller along its internal threaded portion 76. If the sheet rapidly resumes its proper speed, the walking on of the detector roller will be arrested and return spring 74 which has been subjected to a force of compression will restore the detector roller 34 to its normal position as shown in FIG. 3 with a slight mechanical clearance from drive roller 32. If the sheet continues .to decelerate until it stops, the detector roll 34 will continue its axial movement along threaded portion head portion 76. As best shown in FIGS. 1 and 2, engagement of switch actuator button 50 with switch actuator arm 46 will pivot the actuator arm to close motor control switch 42 to stop the drive motor 52.

The mode of operation of the jam detection apparatus as herein above described makes possible an additional checking function. In sheet transport systems for accounting machines, printing machines, and the like the spacing of the individual sheets may be a critical factor in the operation of the machine. Because the diameter of the indicator roll 34 is somewhat larger than the diameter of the drive roll 32, the walking out action will occur each time a sheet passes between the drive roller 32 and the idler rolier 30. By providing a lesser return spring pressure and making -a slight increase in the diameter of rings 36 on detector roll 34, the detector unit can be made to serve the purpose of a sheet gap detector. Thus, if the spacing between successively fed sheets is insufficient to permit the detector roller 34 to reset itself to normal, the walking out" action can be made cumulative. The sheet transport system drive can thus be stopped after several sheets with insuflicient spacing therebetween have passed.

While the present invention has been described in connection with a sheet transport system, it will be understood that the invention is subject to other modifications and adaptations, as in a web feeding apparatus, without departing from the scope of the invention.

What is claimed is:

1. Jam detection apparatus for a sheet in transport comprising first rotating means in engagement with the sheet, means for imparting a continuous rotation thereto, second rotating means in engagement with the sheet and operable to stop its rotation responsive to the stoppage of the sheet and means intermediate said first and said second rotating means and operatively coupled to said first rotating means to transmit a movement from said first rotating means to said second rotating means subsequent to cessation of rotation of second rotating means.

2. I am detection apparatus for a sheet in transport comprising a drive roller in yieldable frictional engagement with the sheet, means for imparting a continuous rotation thereto, rotatable detector means in constant frictional engagement with the sheet and operable to cease rotation responsive to a stoppage of the sheet and means intermediate said drive roll and said detector means and operatively connected .to said drive roll to translate the rotation of said drive roll into a movment of said detector means.

3. Jam detection apparatus for a sheet in transport comprising rotating means in yielding frictional engagement with the sheet, means for imparting a continuous rotation thereto, rotatable detector means in engagement with the sheet operable to stop its rotation responsive to the stoppage of the sheet, means operatively connected to said first rotating means operable to translate the rotation of said first rotating means into linear displacement of said detector means.

4. Jam detection apparatus for a sheet in transport comprising a drive roller in yieldable frictional engagement with the sheet, means for imparting a continuous rotation thereto, rotatable detector means mounted coaxially with said drive roll, having its periphery in frictional engagement with the sheet, and operable to cease rotation responsive to the stoppage of the sheet, means coupled to said drive roll and operable to translate the rotation of said drive roller into rectilineal displacement of said detector means.

5. Jam detection apparatus for a sheet in transport comprising, drive means in yielding frictional engagement with the sheet, means for rotating said drive means at a constant rate, rotatable detector means mounted coaxially on said drive means having its periphery extending beyond the periphery of said drive means and operable .to change its angular velocity responsive to the decreased rate of travel of a sheet in transport, and means operatively connected to and located between said drive means and said detector means responsive to a change in relative velocities of said drive means and said detector means and operable to impart an axial movement to said detector means.

6. Jam detection apparatus for a sheet in transport comprising a drive roller, a threaded projection fixed to and extending coaxially therefrom, means for continuously rotating said drive roller, a cylindrical detector member having a threaded portion mating with said threaded projection, said drive roller and said detector member being in engagement with the sheet in transport,

7 said detector member operable to stop its rotation responsive to the stoppage of the sheet whereby said threaded projection will move said detector member in an axial direction.

7. Jam detection apparatus for a sheet in transport comprising a drive roller, a threaded projection fixed to and extending coaxially therefrom, means for continuously rotating said drive roller, a cylindrical detector member having a plurality of circumferentially extending resilient raised portions and having a threaded portion mating with said threaded projection, said drive roller and said detector member being in engagement with the sheet in transport, said detector member operable to stop its rotation responsive to the stoppage of the sheet whereby said threaded projection will move said detector member in an axial direction.

8. Jam detection apparatus for a sheet in transport comprising a drive roller, a threaded projection fixed to and extending coaxially therefrom, means for continuously rotating said drive roller, a cylindrical detector member having a plurality of circumferentially extending resilient raised portions and having an internal threaded portion mating with said threaded projection, said drive roller and said detector member being in engagement with the sheet in transport, said detector member operable to stop its rotation responsive to the stoppage of the sheet whereby said threaded projection will move said detector member in an axial direction.

9. Jam prevention apparatus for a sheet in transport comprising first rotating means in engagement with the sheet, operating means for imparting a continuous rotation thereto, second rotating means in engagement with the sheet operable to stop its rotation responsive to the stop page of the sheet, means intermediate said first and said second rotating means operable to tnanslate the rotation of said first rotating means into a rectilinear displacement of said second rotating means and means operable to inhibit the operation of said operating means responsive to the rectilinear displacement of said second rotating means.

10. 1am prevention apparatus for a sheet in transport responsive to the stoppage of the sheet whereby said threaded projection will move said detector in an axial direction and means operable to inhibit the operation of said operating means responsive to the axial displacement of said detector member.

References Cited in the file of this patent UNITED STATES PATENTS 1,865,438 Friedernann July 5, 1932 2,793,035 Wroblewski May 21, 1957 2,936,172 Edminster May 10, 1960 

1. JAM DETECTION APPARATUS FOR A SHEET IN TRANSPORT COMPRISING FIRST ROTATING MEANS IN ENGAGEMENT WITH THE SHEET, MEANS FOR IMPARTING A CONTINUOUS ROTATION THERETO, SECOND ROTATING MEANS IN ENGAGEMENT WITH THE SHEET AND OPERABLE TO STOP ITS ROTATION RESPONSIVE TO THE STOPPAGE OF THE SHEET AND MEANS INTERMEDIATE SAID FIRST AND SAID SECOND ROTATING MEANS AND OPERATIVELY COUPLED TO SAID FIRST ROTATING MEANS TO TRANSMIT A MOVEMENT FROM SAID FIRST ROTATING MEANS TO SAID SECOND ROTATING MEANS SUBSEQUENT TO CESSATION OF ROTATION OF SECOND ROTATING MEANS. 